French Onion Grilled Cheese Sandwich (Print version)
A rich French Onion Grilled Cheese Sandwich with jammy caramelized onions, Gruyere, sourdough, and a crisp buttery crust.
# Ingredients:
For the onions
01 -
3 tablespoons unsalted butter
02 -
2 large yellow onions, thinly sliced, about 1 1/2 lb (680 g)
03 -
1/2 teaspoon kosher salt
04 -
1/4 teaspoon black pepper
05 -
2 cloves garlic, minced
06 -
1 teaspoon fresh thyme leaves, or 1/2 teaspoon dried thyme
07 -
3 tablespoons dry white wine or vegetable broth
For the sandwiches
08 -
8 slices sturdy sourdough bread
09 -
2 teaspoons Dijon mustard
10 -
8 oz (225 g) Gruyere cheese, shredded
11 -
2 tablespoons salted butter, softened, for the bread
# Instructions:
01 -
Melt the unsalted butter in a wide skillet over medium heat. Add the onions, salt, and pepper, then cook for 8-10 minutes until softened and reduced.
02 -
Reduce the heat to medium-low and cook for 25-30 minutes, stirring often, until the onions are deep golden and jammy. Add a tablespoon of water if the pan gets dry or dark too quickly.
03 -
Stir in the garlic and thyme for 1 minute. Add the wine or broth and scrape the bottom of the skillet. Cook 2-3 minutes until the liquid is mostly gone. Remove from the heat.
04 -
Spread a thin layer of Dijon on 4 slices of bread. Add half the Gruyere, divide the warm onions over the cheese, then top with the remaining Gruyere and bread.
05 -
Spread softened salted butter on the outside of each sandwich. Cook in a clean skillet over medium-low heat for 3-4 minutes per side, until the bread is deep golden and the cheese is melted.
06 -
Transfer to a cutting board and rest for 1 minute. Slice in half and serve hot while the cheese is melted.
# Good to know:
01 -
Caramelized onions can be made up to 4 days ahead.
02 -
Use low heat for grilling so the cheese melts before the bread gets too dark.
03 -
Recipe makes 4 sandwiches.